What is the evolutionairy theory on the Giraffe?

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Redstang writes:
How did the animal the okapi evolve?

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I would like to thank Mark for his very well thought out descriptions of possible evolutionary scenarios for the giraffe. If he wants to also tackle the okapi I think that would be great, but what your series of questions indicates to me is that you're seeking questions for which we do not have answers.If we find answers to all your questions it only means you're asking the wrong questions. The toilers in the field of science are pondering plenty of unsolved mysteries, and there are tons of questions for which we have no answers. What would it mean if you asked some of these questions, such as does Higg's Boson exist, or is string theory correct, or how did life originate? When we said we didn't know, do you believe it would then be valid to conclude this was evidence of the divine at work? If so, then welcome to the world of Intelligent Design.--Percy

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[This message has been edited by Percipient, 12-15-2001]

You're questions are very welcome. I was just wondering where you were going with them. If not toward ID, then just forget I said anything.There is one more thing I'd like to add. This is not in any way a criticism of Mark's scenarios, just a clarification. The scenarios are only applications of the evolutionary framework to the available evidence and are not evidence themselves. One of the giraffe scenarios may be true, or perhaps it happened some other way. For instance, one possibility Mark doesn't mention when contrasting giraffe and impala development is that their common ancestor may have become separated into populations in different geographical regions before being reunited on the savannah of modern day Africa. And adding that scenario probably still doesn't cover all the bases, because in general in any field as study as you expand the details in the scenarios the necessity for subdividing them arises.--Percy

It's not a requirement, but it is one of the possibilities.--Percy

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Mark24 writes:
The Giraffe isn't misproportioned, it is OPTIMALLY proportioned for its lifestyle.

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An interesting question often asked about ID (which I know isn't advocated by Redstang, I introduce it for another reason) is why God's designs are identical with evolution. This often comes up when people question why God would design humans so poorly, eg, why the appendix, why blood vessels in front of the retina, why a body cavity design best suited for horizontal positioning, why tonsils, and so forth. The argument is that good enough designs, vestigial organs, etc, are what one would expect of evolution, not of a divine designer.Assuming consistent arguments are preferable, could it instead be argued that the giraffe body design is good enough for its ecological niche, rather than optimal?--Percy

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[This message has been edited by Percipient, 12-17-2001]

Putting on my moderator hat...I don't know that it's that relevant to the discussion what John Paul meant when he mentioned a 2000 year-old Bible.Anyone who wants to debate who's a hypocrite can open a new thread at the Coffee House Forum.--Percy

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Fred Williams writes:
Even if I grant you a partially functioning valve, how many lucky mutations would be needed to produce this primitive valve?

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Valves had already evolved before the giraffe neck's need for them. We possess such valves ourselves in our legs, only they're in veins instead of arteries. When these valves malfunction it becomes evident as varicose veins.The appearance of these valves in arteries in the giraffe's neck only required a minor mutation moving a valve gene from a leg vein to a neck artery.Of course, this doesn't answer your question, but merely moves it back in time. As land creatures evolved longer and longer legs, how did the valves making taller animals possible evolve?--Percy